Construct, also called hypothetical construct or psychological construct, in psychology, a tool used to facilitate understanding of human behaviour. All sciences are built on systems of constructs and their interrelations. The natural sciences use constructs such as gravity, temperature, phylogenetic dominance, tectonic pressure, and global warming. Likewise, the behavioral sciences use constructs such as conscientiousness, intelligence, political power, self-esteem, and group culture.

In a sense, a psychological construct is a label for a cluster or domain of covarying behaviours. For example, if a student sees another sitting in a classroom before an examination biting her nails, fidgeting, lightly perspiring, and looking somewhat alarmed, the interpretation might be that she is experiencing test anxiety. In that case, test anxiety is a label for the covariation that is attributed to the observed behaviours. Some scientists extend that conceptualization and suggest that test anxiety is an underlying cause of those behaviours. Used in that way, a construct is a hypothesized cause for the observed behavioral covariations.

A construct derives its name from the fact that it is a mental construction, derived from the general scientific process: observing natural phenomena, inferring the common features of those observations, and constructing a label for the observed commonality or the underlying cause of the commonality. Any given construct derives its scientific value from the shared meaning it represents for different people. That is, if a construct is clearly articulated and the phenomena it encompasses are clearly defined so that different people think similarly about it, then it becomes a useful conceptual tool that facilitates understanding and communication. Once defined, constructs become objects of conceptual scrutiny in their own right. In other words, psychologists hypothesize both whether certain behaviours will covary and whether the clusters of covarying behaviours (i.e., constructs) tend to covary in meaningful ways with other constructs.

Constructs summarize behavioral domains and allow extrapolations to unobserved behaviours. For example, after the observation of a student with test anxiety is remarked upon to another student, that person might assume the occurrence of, or attribute, more behaviours to the classmate (such as crying or grinding of teeth) than were originally observed. That extrapolation underlies much of the psychologist’s predictive power. If certain behaviours can be observed, then other unobserved behaviours can be predicted to occur in the future. The accuracy of those predictions depends largely on the quality of the conceptual and psychometric foundations of the construct in question (i.e., construct validity).

Constructs are hypothetical. They exist as concepts but not as tangible entities. Some constructs, however, become so familiar and ingrained in common use that most people assume their manifest existence. For example, it might be supposed that gravity can be shown by dropping an object to the floor. All that has been demonstrated in that case, however, is the falling of an object, not gravity. Gravity is a label for the hypothetical cause of the falling object, not the observable event. The same scenario can be built around any psychological construct—for example, extroversion or quantitative ability. Extroversion is not observable, but extroverted behaviours are, and those are summarized by evoking a construct label and inferring that the person who exhibited those behaviours is extroverted to some degree.

Constructs are the building blocks of scientific theories. Psychologists who are interested in studying and understanding human behaviour are interested in identifying behavioral regularities and their causes. Constructs help research and applied psychologists to summarize the complex array of observed behaviours, emotions, and thoughts that people produce in their day-to-day activities. Research may focus on identifying and clarifying construct boundaries, or determining which constructs relate to other constructs, as a basis for theorizing functional relationships between systems of constructs. Applied psychologists use constructs to make decisions about how to treat people with certain psychological disorders or whom to select, train, and promote for certain jobs or careers in organizations.